Applicability of SIE/Sies/GITMO Fitness Criteria to Therapy-Related and AML-MRC Receiving CPX-351: Results from a Large, Retrospective, Multicentric, Observational Study

Introduction: Treatment of therapy-related AML (t-AML) and AML evolving from an antecedent myelodysplastic syndrome (AML-MRC) represent a clinical unmet need being characterized by an unfavorable outcome. Among the emerging treatment options, CPX-351 has been approved by Regulatory Authorities for the treatment of fit patients (pts) affected by these AML sub-types. Although patented for the treatment of pts fit for intensive chemotherapy, in real-life CPX-351 is also administered to unfit ones, raising the case of tolerability in these categories. Among scores for fitness definition, SIE/SIES/GITMO criteria were extensively validated in large cohorts of AML pts receiving intensive chemotherapy and are increasingly incorporated into clinical trials. However, since these criteria have not been tested yet in the subset of t-AML and AML-MRC, we investigated their applicability in these pts receiving CPX-351. Methods: Patients classified as t-AML or MRC-AML according to WHO2016 classification receiving at least one cycle of CPX-351 were included in the present analysis. Genetic and cytogenetic data were classified according to ELN2017 risk stratification. SIE/SIES/GITMO criteria were retrospectively applied to the whole series to categorize pts as fit or unfit to intensive chemotherapy (Ferrara et. al, Leukemia 2013), aiming at evaluating early-death rate and overall survival (OS). We also verified if ELN2017 risk-stratification might provide further information about long-term outcome, independently of fitness assessment. Results: This retrospective study includes 398 pts with t-AML (19.3%) or AML-MRC (80.7%) enrolled from 29 Italian Institutions between 2018 and 2023. Median age was 65 years (range 32-79), with a slight male prevalence (56.8%). According to SIE/SIES/GITMO criteria, 323 (81.2%) pts qualified as fit and 75 (18.8%) as unfit. Based on ELN2017 risk stratification, 17 (4.3%) pts were classified as favorable, 162 (40.7%) as intermediate, 217 (54.5%) as adverse risk. Only 2 (0.5%) pts were not classifiable due to incomplete genetic data. No differences were observed in terms of ELN2017 risk distribution among the fit and unfit groups. After first induction, 188 of 323 (58.2%) fit and 42 of 75 (56%) unfit pts achieved a complete remission (CR), for a total of 230 (57.8%) pts entering CR. From CPX-351 start, 18 and 55 deaths at 28 days and at 100 days occurred, respectively. Early death rate at these early timepoints statistically differed between the